Financial Instruments - Derivative Instruments at Gross Fair Value (Details) - Level 2 - USD ($) $ in Millions	Dec. 28, 2019	Sep. 28, 2019
Other current assets and other non-current assets | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	$ 1,952	$ 2,121
Other current assets and other non-current assets | Interest rate contracts
Derivative assets:
Fair value of derivative assets	475	685
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	1,625	1,798
Other current assets and other non-current assets | Derivatives designated as accounting hedges | Interest rate contracts
Derivative assets:
Fair value of derivative assets	475	685
Other current assets and other non-current assets | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative assets:
Fair value of derivative assets	327	323
Other current assets and other non-current assets | Derivatives not designated as accounting hedges | Interest rate contracts
Derivative assets:
Fair value of derivative assets	0	0
Other current liabilities and other non-current liabilities | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	1,458	1,501
Other current liabilities and other non-current liabilities | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	57	105
Other current liabilities and other non-current liabilities | Derivatives designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	964	1,341
Other current liabilities and other non-current liabilities | Derivatives designated as accounting hedges | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	57	105
Other current liabilities and other non-current liabilities | Derivatives not designated as accounting hedges | Foreign exchange contracts
Derivative liabilities:
Fair value of derivative liabilities	494	160
Other current liabilities and other non-current liabilities | Derivatives not designated as accounting hedges | Interest rate contracts
Derivative liabilities:
Fair value of derivative liabilities	$ 0	$ 0